Prussian blue nanoparticles anchored on activated 3D printed sensor for the detection of L-cysteine

Abstract

The use of 3D printing technology has enabled the development of low-cost and versatile electrochemical sensors. Commercial conductive filaments have been widely used due to their easiness of acquisition ready for application, and the possibility of surface modification. Generally, these filaments are composed of polymers and conductive material. However, it can present different compositions according to the manufacturing, which includes other additives and impurities. Iron has been reported as one of these impurities in conductive filaments based on polylactic acid and graphene. In this case, we have explored the presence of iron species for the electrochemical synthesis of stable nanoparticles of Prussian blue on 3D printed graphene electrodes. Prussian blue was used for the catalyst and electro-oxidation of L-cysteine amino acid, which is a biomarker related to several health problems and neurodegenerative diseases, such as Alzheimer's and Parkinson's. An arrangement of all 3D printed electrodes was used and presented comparable results to a conventional electrodes array. Also, the proposed sensors have shown good sensitivity, selectivity in presence of other amino acids, repeatability, and intra-day reproducibility for L-cysteine detection, compared to other 3D printed sensors obtained at different ages. The detection of L-cysteine was performed in spiked human blood serum samples, demonstrating no significant matrix interference.